BIOL 3051 Chapter Notes - Chapter 8.0: Hcn Channel, Ziconotide, Calcium Channel
24 Apr 2020
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Ca2. x & nt release n-type: ca2. x especially ca2. 2 (n-type ca2+ channel) regulate release of nt from synaptic neurons, pre-synaptic knobs have n-type calcium channel, nerve impulse cause influx of ca2+ . Ca2+ allow nt release into synaptic cleft: ca2+ allows for fusion of nt vesicles. Snares complex is calcium dependent: calcium entry binds to synaptotagmin of snare complex induces fusion of membrane. N-type (ca 2. 2) ca2+ channels: high expression in presynaptic terminal, ziconotide: is peptide based on conotoxin used for analgesia. Hydrophilic blocker of n-type voltage gated calcium channel. So no nt release blocks depolarization of post synaptic neuron. Gabapentinoid action at a2y subunit: gabapentin does not directly modulate gaba receptors, gabapentin & pregabalin bind to a2 auxiliary subunit of calcium channels (responsible for conductance) Reduce conductance (30%) reduce release of nt. P/q type (ca2. 1) ca2+ channels: highly expressed in presynaptic terminals, w-agatoxins are only specific p/q blockers. Use dependent, less effective when channel activated.
